Function CompressImage

Engine/lib/squish/squish.cpp:157–209

}

void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags, float* metric )
{
	// fix any bad flags
	flags = FixFlags( flags );

	// initialise the block output
	u8* targetBlock = reinterpret_cast< u8* >( blocks );
	int bytesPerBlock = ( ( flags & ( kDxt1 | kBc4 ) ) != 0 ) ? 8 : 16;

	// loop over blocks
	for( int y = 0; y < height; y += 4 )
	{
		for( int x = 0; x < width; x += 4 )
		{
			// build the 4x4 block of pixels
			u8 sourceRgba[16*4];
			u8* targetPixel = sourceRgba;
			int mask = 0;
			for( int py = 0; py < 4; ++py )
			{
				for( int px = 0; px < 4; ++px )
				{
					// get the source pixel in the image
					int sx = x + px;
					int sy = y + py;
					
					// enable if we're in the image
					if( sx < width && sy < height )
					{
						// copy the rgba value
						u8 const* sourcePixel = rgba + 4*( width*sy + sx );
						for( int i = 0; i < 4; ++i )
							*targetPixel++ = *sourcePixel++;
							
						// enable this pixel
						mask |= ( 1 << ( 4*py + px ) );
					}
					else
					{
						// skip this pixel as its outside the image
						targetPixel += 4;
					}
				}
			}
			
			// compress it into the output
			CompressMasked( sourceRgba, mask, targetBlock, flags, metric );
			
			// advance
			targetBlock += bytesPerBlock;
		}
	}
}

void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags )
{